Electric control system



March 22, 1932. w. w. WILLIAMS ELECTRIC CONTROL SYSTEM Filed July 31,1950 a M H Y L M W n O. N TW R N 0 W yn mw L. a m

Patented Mar. 1932 UNITED STATES PATENT OFFICE WALTER w. WILLIAMS, 0]BLOOmGTON, ILLINOIS, ASSIGNOB 'I'O WILLIAMS OIL-O- IATIG HEATING-CORPORATION, IILINOIB Application filed July 81,

This invention relates to improvements in the electric control systemfor electrically operated and actuated domestic fluid fuel controlledeither by the commercial circuit,

or one dependent upon it, including a room thermostat which may be setat the desired temperature of the ,room or portion of the building inwhich it is located and will act to close the circuit to the burnermotor when the temperature descends below and open the circuit totheburner motor when the temperature reaches or extends above thedesired degree. Fluid fuel burners of this type usually include anelectric ignition system as well as such safety devices as may berequired by the Fire Underwriters. The ignition system usually includesa transformer with an ignition 7 switch for closing the circuit to thetrans burner mechanism to ignite the 7 after breaking the circuit to thetransformer.

former and causing an electric spark when the fluid fuel is initially suplied to the uel and there- The safet devices usually include a boiler,control w ich is normally closed and will act to breair the circuitwhen the degree of tempreaches the perature or pressure within theboiler aptric switch responsive to presence or absence ofcombustion'within the heater, which if combustion occurs will permit theburner to operate and if combustion fails to occur will cause the burnerto cease operating.

It is an object of this invention to provide a. system such as abovedescribed for controlling the operation of a domestic fluid fuel burnerwhich includes an ignition switch I which is normally ofin when theburner is idle and which will 21; redetermined time after the operationo t e automatically closed urner motor is initiated and to include inthe circuit between the source and burner motor an additional safetydevice which will break the circuit to the motor in a-predetermined timethe motor does not start the circuit to the danger limit, as well as anelecas including a casing mostat T, ,0 with a' boiler ,control B, ofcommercial de- Oll' BLOOMINGTON, ELIHOIS,"A CORPORATION 01' ELECTRICCONTROL SYSTEM 1930. Serial No. 472,137.

after it opens said safety device will break I motor; and which uponnormal operation of the burner and the closing of the switch responsiveto combustion conditions will be shunted out and the burner willcontinue to operate until the room thermostat opens the motor circuit,but if the burner flame becomes extinguished for any reason afterignition the switch responsive to combustion conditions will open andthe full I strength of the commercial current passing through saidsafety device will cause it to break the motor circuit.

With these and other objects in view refer-' ence is made to theaccompanying sheet of drawing which illustrates a preferred form of thisinvention with the understanding that minor detail changes may be madewithout departing from the scope thereof.

The drawing is a diagrammatical view of this improved system as a pliedto a com mercial type of domestic fluid fuel burner mechanism installedin connection with a commercial type of domestic heater.

The fluid fuel burner mechanism is shown 1 supported upon a standard 2mounting an electric motor operating a fanwithin under pressure througha draft pipe 4 opening through the wall 5 of the domestic heater intothe combustion chamber 6 thereof. As is customary in this type of burnerfluid fuel is supplied through a uel pipe 7 and is discharged through anozzle 8 into the combustion chamber 6 where it is ignited by a ahousing 3 to direct air spark jumping between electrodes 9 in circuitwith the transformer 10.

The wiring diagram-includes a room thercommercial, design, in circuitsign,- a switch responsive to combustion condition S, of commercialdesign, and an ignition switch I. As

above stated certain types of commercial burners include in their c0'n-'trol systems an ignition switch which is nor mally open and which isclosed for a predetermined time by the energization of the burner motor.In this particular type illus-' trated the ignition switch I is shown inthe open position. The burner motor is mounted in a casing supported 'ontrunnions 11 rotatable upon bearings in the burner casing. One of thesetrunnions 11 is providedwith a connection 12 to the ignition switchcarrier plate 13 whereby the force of reaction when the motor isenergized imparts a rotative movement to the trunnion 11, causing thecarrier plate 13 to close the ignition switch and thereafter release thecarrier plate and allowing the dash pot 11L to return the ignitionswitch to open position. The applicant has seen fit to illustrate theembodiment of this invention in connection with the above describedcommercial ignition switch oper ating mechanism more fully illustratedand described in United States Patent 1,783,405 dated December 2, 1930.However, understood that this invention is not limited to thisparticular commercial construction as any means operated upon energizingthe burner motor to actuate the ignition switch to first close and thenopen, such as the pressure created by a fan or a pump operated by themotor, may be employed.

This invention contemplates the insertion in the control. circuit of athermal circuit breaker C, of commercial design, which may be adjustedso that when the commercial current has passed through the thermalmember thereof for a predetermined time the said member will release aspring pressed switch to break the circuit and which switch maybe resetmanually and be held in closed position by the cooled thermal member.This circuit breaker G is placed in the circuit to normally conduct. theincoming commercial current about the switch S to the motor and when theignition I switch is closed to shunt out the secondary circuit breakerC.

In accordance with this invention when the room thermostat calls forheat byclosing, the incoming current from the commercial line followsthrough the wire 15, passing through the closed thermostat T, thenormally closed boiler control B, through wire 16, circuit breaker C tothe motor, and back by the way of wire 17 to the source, whereby thecircuit to the motor is completed and should the motor through anydefect therein fail to operate, the circuit breaker will automaticallybreak the circuit after a predetermined time, thereby preventing furtherinf jury by the continued passage of the current through the motor, Thenormal operation of the motor when started closes the ignition switch Iwhich is a three terminal switch-of the mercury tubefltype, as shown,whereby a it is/to be circuit is completed by a wire 18 from-wire 15,through the closed ignition switch I and by wire 19 through thetransformer '10 back to wire 17, and at the same time a cir'- cuit isclosed by wire 18- fromthe wire 15 through'the ignition switch I,through wire 20 and through wire 16 to the motor and then back to wire17. This allows the motor to continue to operate while reducing thestrength of the current passing through the circuit breaker and at thesame time energizes the ignition transformer. Should the fluid fuel failto ignite, as the ignition switch is normally opened after apredetermined time, thereafter the 'full strength of the current Willpass through the circuit breaker and cause it to open the circuit to themotor. When the fluid fuel is ignited, the switch S, normally open andresponsive to combustion, closes a circuit, through wire 21 to wire 16on each side of the circuit breaker C, thereby shunting out the circuitbreaker and connecting the motor circuit directly to the commercial lineand causing the motor to operate as long as the switch S, boiler controlB and room thermostat T remain closed. What I claim is:

1. An electric control system for an electrically operated and actuateddomestic fluid fuel burner including a burner motor in a motor circuit,an ignition device in an ignition circuit having an ignition switchtherein normally open, means actuated upon m1- .tiating the operation ofthe motor to close the ignition switch, and a circuit breaker in themotor circuit adapted to break the motor circuit upon failure of themotor to operate, and means to shunt out the circuit break 81 upon theclosing of the ignition switch.

2. An electric control'system for an electrically operated and actuateddomestic fluid fuel burner including a burner motor in a motor circuit,an ignition device in an ignition circuit having an ignition switchtherein normally open, means actuated upon initiating the operation ofthe motor to close the i nition switch for a predetermined time andfliereafter'open the ignition switch, a circuit breaker in the motorcircuit, and a shunt circuit including the ignition switch for shuntingout the circuit breaker while the igcuit breaker in the motor circuit,and a shunt circuit including the ignition switch for shunting out thecircuit breaker while the ignition switch is closed, and an additionalshunt circuit including a normally open switch responsive to combustionconditions adapted to close upon ignition of the fuel and shunt out thecircuit breaker before the opening of the ignition switch.

4. An electric control system for an electrically operated and actuateddomestic fluid fuel burner including a burner motor in a motor circuit,an ignition device in an ignition circuit having an ignition switchtherein normally open, means actuated upon initiating the operation ofthe motor to close the ignition switch for a predetermined time andthereafter open the ignition switch, a circuit breaker in the motorcircuit, two shunt circuits each adapted to shunt out the circuitbreaker, one shunt circuit including the ignition switch, a normallyopen switch in the other shunt circuit adapted to close uponestablishment of combustion, whereby the closing of the motor circuitand initiation of the operation of the motor shunts out the circuitbreaker while the ignition switch is closed and ignition of the fuelshunts out the circuit breaker before the ignition switch is opened.

5. An electric control system for an electrically operated and actuateddomestic fluid fuel burner including a burner motor in a motor circuit,av circuit breaker in the motor circuit, two normally open shuntcircuits each adapted to shunt out the circuit breaker, means actuatedby the operation of the motor to close one shunt circuit for apre-determined time only and means actuated upon establishment ofcombustion to close the other shunt circuit.

6. An electric control system for an electrically operated and actuateddomestic fluid fuel burner including a burner motor in a motor circuit,a circuitcbreaker in the motor circuit, two normally open circuits eachadapted to shunt out the circuit breaker, means actuated by theoperation of the motor to close one shunt circuit for a predeterminedtime and thereafter open the said shunt circut, and means actuated uponestablishment of combustion to close the other shunt circuit.

7. An electric control system for an electrically operated and actuateddomestic fluid fuel burner including a burner motor in a motor circuit,a circuit breaker in the motor circuit, two normally open circuits eachadapted to shunt out the circuit breaker,

- means actuated by the operation of the motor to close one shuntcircuit for a predetermined time and thereafter open the said shuntcircult, and means actuated upon establishment of combustion to closethe other shunt circuit before the first shunt circuit is opened.

WALTER W. WILLEAMS.

